1. Field
The following description relates to a codebook used in a multiple-input multiple-output (MIMO) communication system, and more particularly, to a rotating reference codebook that includes codewords from a discrete Fourier transform (DFT) codebook.
2. Description of Related Art
Researches are being conducted to provide various types of multimedia services and to provide high quality and high speed data transmission in a wireless communication environment. One potential solution is a multiple-input multiple-output (MIMO) communication system using multiple channels.
In a MIMO communication system, a base station and terminals may use a codebook to enhance the channel environment between the base station and the terminals. A particular space may be quantized into a plurality of codewords by quantizing space according to a predetermined criterion. The plurality of codewords that are generated may be stored in the base station and in the terminals. Each of the codewords may be a vector or a matrix.
For example, each of the terminals may select one matrix or vector corresponding to channel information from matrices or vectors included in a codebook, based on a channel formed between the base station and each of the terminals. The base station may verify channel information based on the received matrix or vector selected by the terminal. For example, the selected matrix or vector may be used when the base station performs precoding or performs transmission using multiple antennas.